Method of producing inorganic fibrous material



Patented Nov. 23, 1943 ME'rnon or raonucme INORGANIC muons MATERIALWilliam M. Ber-gin, Granville, and Allen L. Simison, signments,

Newark, Ohio, assignors, by mesne asto Owens-Corning FibergiasCorporation, Toledo, Ohio, a corporation of Delaware No Drawing.

Original application July 26 1938,

Serial No. 221,460, now Patent No. 2,252,157,

' dated August cation October 11,

1940, Serial No. 360,818

Divided and this appli- 2 Claims. (61. 154-28) The present inventionrelates to a method of producing mineral wool bats, especially thosecomprising glass wool, slag wool, rock wool or the like, andparticularly to a method of treating and binding mineral fibers to forman unusually light; weight, strong, self-sustaining, resilient bathaving fixed dimensions. The invention has special applications to glasswool, heat or sound insulating bats made in accordance with theteachings of the patent to 'Slayter and Thomas 2,133,236. I V

This application is a division of our copending application, SerialNumber 221,460, filed July 26, 1938, now Patent No. 2,252,157, datedAugust 12, 1941.

An object of the present invention is to provide a method for forming afibrous bat having the aforementioned properties of strength, highresilience and fixed dimensions, combined with unusually light densitiesof about 1 lb. per cubic ft. and ranging up to any density, such, forexample, 3 or 9 lbs. per cubic ft., according to the particular purposesto which the bat is to be put. Ordinarily, for house insulationmaterial, a light density of about 1 /2 lbs. per cubic ft. is desirable.Such bat may have sufficient structural rigidity so that the bats may behandled, assembled into place without reenforcing members such as acardboard core, or outer wrappings of paper, or reenforcing stitchings.

For better heat insulating qualities desirable for use in refrigerators,stoves, bottle coolers and the like, a 3 lb. density, more or less, isgen- ,erally desirable. Higher densities of about 5 to 7 lbs. per cubicft. are preferable for boiler insulation, industrial ovens, board orsheet type of material or the like. 1

The present, invention is particularly suitable for producing railroadinsulation where the.

lightest density possible is desired coupled with high structuralstrength capable of withstanding the jolting and vibration incident torailroad car use. A bat made in accordance with the present inventionmay have an extremely light density of about 1 /2 lbs. per cubic ft.,and suflicient structural strength that it may be mounted inside therailroad car wall panel and not settle or gradually break up due to thedestructive vibra tion of the train.

Another object of the present invention is to provide a method'ofproducing a heat and sound insulating body having the foregoingproperties while using a minimum amount of binding or stiffeningmaterial to accomplish the same.

Another object, is to provide a method of incorporating in a bat astiffening or binding material which will maintain its propertiesthrough wide temperature ranges, and will not sag or become brittle asthe temperature rises or falls.

Heretofore numerous binders have been suggested and used for bondingtogether mineral wool fibers into bats. Most generally such materials asasphalt, gypsum, starch, r'osin, linseed 1 particularly if it containedan alkaline constituent.

We have discovered that a fibrous bat having highly superior propertiesmay be produced by incorporating in the bat, by the method of thepresent invention, a very small amount of thermosetting, condensationproduct. This may be and preferably is combined with an incompatibleoleaginous lubricant such as oil, fatty material, or the tempering oilemulsion patented and described in the Williams and Bone PatentNo.2,083,132, or their patent No. 2,107,284.

Various thermosetting condensation products may be used, as, forexample, phenol formaldehyde, urea formaldehyde, or variousmodifications and variations of these synthetic thermosetting materialswhich may be made by one skilled in the art to produce a resinoriginally in a liquid state, and finally in a hard, strong, solid mass.For ordinary purposes Bakelite,originally as water soluble material, hasbeen found very satisfactory for use in the present invention.

A small amount of the thermosetting stiffening agent. may be added tothe tempering oil or lubricating mixture and applied directly to theblasted fibers. Preferably, however, the combination is first emulsifiedwith water and then sprayed on the glass fibers as they are building upto mat formation upon a conveyor.

Various proportions of materials may be used, although it, has beenfound that a'small proportion of only about /2% to 1 /4% of Bakelite perweight of wool is sufficient for ordinary purposes.

When minute amounts of about /g to of a percent are used, the bat hasmaterially increased stiirness. and resilience, and reduced limpness,but it is not rigid or still. with increased amounts, the bat assumes asemi-rigid form, and with the higher amounts, a fair amount of rigidityand strength are attained. The bat is still resilient and tough and canwithstand considerable bending or compression stress without destroyingits properties,

The finished bat may thus have about /2 to parting high structuralstrength with a minimum quantity of material.

In accomplishing this desirable distribution,

.the thermosetting material originally in liquid achieve a certainamount of flexibility and yieldbright stock hydrocarbon oil, mineraloil, paraflin .oil, petroleum oil or the like in amounts or about 2% orso, as desired. Metallic soap, waxes, fats, ammonia or the like may alsobe added to increase water repellancy of the bat if desired. Bentoniteor the like may be added to act as an emulsifier, and to increase theheat insulating properties of the bat.

The method of applying the emulsion or mixture of lubricant and bindermay be similar to any of those now in use. Ordinarily it is preferableto spray the mixture onto the fibers as they build up into mat formationand are continuously withdrawn in mat formation. It is desirable toaccomplish this process over the fiber deposition zone in order tocontrol the deposition and preferably to apply sumcient heat toevaporate the aqueous phase of the emulsion, leaving the lubricant andbinder or stifi'ening agent distributed over the fibers. After removalfrom the deposition zone, it is desirable to heat treat the stiifeningagent and cause it to polymerize into a final set, thus adding stifinessand a controlled amount of rigidity and resilience to the bat. This maybe accomplished by any of the usual methods as, for example, by passingthe material between rollers or between caterpillar belts having hot airor th like passing continuously therethrough in order to impartsufficient heat to polymerize the thermosetting agent. The caterpillarbelt will also hold the bat down to a predetermined fixed dimension asthe thermosetting binder hardens.

The reason why such a small amount of binder, as, for example, an amountless than or about 1% incorporated in the bat by the method oi thepresent invention can effect such striking increases in strength andstiifness of the bat is not fully understood, although several reasonshave been advanced to explain the phenomenon. From observations under amicroscope, it was noted that at a large number of intersections offibers, it appear'ed that the stifiening agent congregated in very smallamounts and coated the intersections with rounded smooth concavesurfaces in a manner similar to a fillet, thus imability under stress.

It isalso considered possible that the oleaginous lubricant would form auniform, homogeneous coating over the individual fibers, and that anincompatible thermosetting resin acts as a hinder or stifienerindependently. The lubricant over the fibers, however, would provide asumcient amount of yieldability so that the bat would attain a highdegree of resilience and strength without causing excessive rigidity andembrittlement of the individual fibers.

Various modifications and variations may be resorted to within thespirit and scope of the present invention as defined in the appendedclaims.

' We claim:

1. Themethod of producing a light weight, strong, resilient fibrous batof glass fibers, which comprises simultaneously depositing from agaseous atmosphere, glass fibers and an aqueous emulsion of petroleumoil, an emulsifying agent, and a thermosetting aldehydecondensationproduct in water-soluble form,'evaporating the aqueous phase of saidemulsion and forming a loose,

, fiuify mat of glass fibers having the remaining constituents of saidemulsion and the aldehyde condensation product disposed over the fibers,the incompatible nature of said 011 and the said condensation productcausing the two to separate on the fiber surfaces, and then applyingheat to thermally set said condensation product to conv ert it to awater-insoluble state and stiffen said mat.

[2. The method of producing a light weight,

strong, resilient fibrous bat or glass fibers, which,

comprises simultaneously depositing from a gaseous atmosphere, glassfibers and a fiber-treating material comprising an emulsion ofoleaginous lubricant in water and a partially reacted phenolformaldehyde in water solution incompatible with said lubricant,removing the water from said treating material and forming a loose,fiuiiy mat with the lubricant and the phenol formaldehyde distributed astwo' phases over the fiber surfaces, and then completing the reaction ofsaid phenol formaldehyde to cause said mat to stiffen into bat form.

WILLIAM M. BERGIN. ALLEN L. SIMISON.

